Vehicular refrigeration cycle apparatus

ABSTRACT

A vehicular refrigeration cycle apparatus where, at the time of startup before starting the operation of a compressor, the speed of a condenser-use blower which blows outside air toward the condenser is increased in accordance with the air-conditioning load. Due to this, the operating noise of the condenser-use blower familiar to the users becomes masking noise helping to prevent the operating noise of the compressor from being heard by the user and the unfamiliar operating noise of the compressor can be kept from being heard by the user.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicular refrigeration cycle apparatus which is provided with an electric compressor.

2. Description of the Related Art

In the past, there has been known a vehicular refrigeration cycle apparatus which is provided with an electric compressor. In this type of electric compressor, it is possible to adjust the speed of the electric motor so as to easily change the discharge flow.

For example, in the vehicular refrigeration cycle apparatus used for the vehicular air-conditioning system of Japanese Patent Publication (A) No. 8-219071, at the time of startup of the electric compressor, to avoid liquid compression, the speed is kept low, then the speed is quickly increased so as to obtain a discharge flow in accordance with the air-conditioning heat load.

SUMMARY OF THE INVENTION

In this respect, when mounting a vehicular refrigeration cycle apparatus which is provided with an electric compressor in an electric vehicle not mounting an internal combustion engine (engine) for driving the vehicle (including fuel cell vehicles etc.), since the electric vehicle has no operating noise of an internal combustion engine, as shown in Japanese Patent Publication (A) No. 8-219071, if increasing the speed of the electric compressor in accordance with the air-conditioning heat load, the operating noise of the electric compressor will sometimes end up becoming audible to the user. As a result, the operating noise of the electric compressor will sometimes bother the user.

Further, when mounting this type of vehicular refrigeration cycle apparatus in a hybrid car where the internal combustion engine sometimes stops when the car is stopped, if operating the electric compressor while the internal combustion engine is stopped, the operating noise of the compressor, which had been masked by the operating noise of the internal combustion engine during operation of the internal combustion engine, will sometimes end up being heard by the user. As a result, the problem ends up surfacing of the operating noise of the electric compressor bothering the user.

In particular, when the vehicle is stopped or when parking or otherwise driving at an extremely low speed, there is no noise caused by the friction between the tires and road surface (road noise), so if operating the compressor in the state where the internal combustion engine is stopped, the operating noise of the electric compressor will end up being heard not only by persons inside the vehicle, but also outside the vehicle. Such unfamiliar operating noise of the electric compressor, which had been masked by the road noise at the time of normal driving, ending up being heard is also a cause of users ending up mistakenly believing the electric compressor is malfunctioning.

In consideration of the above, the present invention has as its object the provision of a vehicular refrigeration cycle apparatus which is configured to be able to keep unfamiliar operating noise of an electric compressor from ending up being heard by the user.

To achieve this object, the present invention provides a vapor compression type vehicular refrigeration cycle apparatus adapted for use in a vehicle having a drive-use electric motor (DM) as a drive source for powering the vehicle and able to be driven by the drive power output from the drive-use electric motor (DM), the vehicular refrigeration cycle apparatus comprising:

an electric compressor (11) which is driven by the supply of electric power and compresses and discharges a refrigerant;

a masking noise generating means (12 a, 21, 51) for generating masking noise helping to keep an operating noise of the electric compressor (11) from being heard by a user; and

a masking noise control means (40 a) for controlling operation of the masking noise generating means (12 a, 21, 51), wherein the masking noise control means (40 a) makes the masking noise generating means (12 a, 21, 51) start to generate masking noise before the start of operation of the electric compressor (11).

According to this, masking noise helping to keep the operating noise of the electric compressor (11) from being heard by a user is generated before the start of operation of the electric compressor (11), so it is possible to keep unfamiliar operating noise of the electric compressor (11) from ending up being heard by the user.

Note that, the masking noise is preferably noise which a user is used to hearing when driving, for example, the above-mentioned road noise. Further, the above “vehicle . . . able to be driven by the drive power output from the drive-use electric motor (DM)” is not limited to electric vehicles, but includes hybrid cars etc. in meaning.

In the vehicular refrigeration cycle apparatus of the present invention, the masking noise control means (40 a) may make the masking noise generating means (12 a, 21, 51) generate masking noise when the vehicle is stopped or the vehicle is being driven at a predetermined reference vehicle speed (KVv) or less.

According to this, it is possible to make the masking noise generating means (12 a, 21, 51) generate masking noise under vehicle driving conditions where no road noise is generated such as when the vehicle is stopped or the vehicle is being driven at a predetermined reference vehicle speed (KVv) or less. Further, by having this masking noise heard by the user, it is possible to effectively keep the unfamiliar operating noise of the electric compressor (11) from being ending up heard by the user.

In the vehicular refrigeration cycle apparatus of the present invention, in the vehicular refrigeration cycle apparatus, the masking noise generating means may be configured by a condenser-use blower (12 a) blowing air toward a condenser (12) which radiates heat from a refrigerant which is discharged from an electric compressor (11).

In general, the operating noise which is produced from a condenser-use blower (12 a) arranged under the hood is noise which persons outside the cabin are used to hearing. Therefore, by forming the masking noise generating means (12 a, 21, 51) by the condenser-use blower (12 a), it is possible to keep unfamiliar operating noise of the electric compressor from ending up being heard by persons outside the cabin.

In the vehicular refrigeration cycle apparatus of the present invention, the masking noise control means (40 a) may be designed to make a blowing rate of the condenser-use blower (12 a) increase along with an increase of a heat load of a refrigeration cycle.

Here, along with the increase of the heat load of the cycle, the refrigerant discharge capacity required from the electric compressor (11) (discharge flow) increases, so the speed of the electric compressor (11) has to be increased. Therefore, by increasing the blowing rate of the condenser-use blower (12 a) along with the increase of the heat load of the cycle, the blowing rate of the condenser-use blower (12 a) will not be unnecessarily increased and electric power will not be wastefully consumed.

In the vehicular refrigeration cycle apparatus of the present invention, the masking noise generating means may also be configured by an evaporator-use blower (21) which blows cabin venting air toward an evaporator (14) which causes evaporation of a refrigerant taken into the electric compressor (11).

Here, the operating noise of the evaporator-use blower (21) for blowing air into the cabin is noise which people in the cabin are used to hearing. Therefore, by configuring the masking noise generating means (12 a, 21, 51) by the evaporator-use blower (21), it is possible to keep unfamiliar operating noise of the electric compressor from ending up being heard by persons in the cabin.

In the vehicular refrigeration cycle apparatus of the present invention, the masking noise generating means may be configured by an audio system (51) which outputs predetermined noise.

According to this, it is possible to generate masking noise which does not bother the user from masking noise generating means (12 a, 21, 51). For example, the masking noise generating means (12 a, 21, 51) may be configured by a car stereo or other audio system (51) or may be configured by an audio system (51) playing back sound corresponding to road noise.

Note that the reference numerals in parentheses attached after the above means are examples showing correspondence with specific means described in the embodiments explained later.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings, wherein:

FIG. 1 is a view of the overall configuration of a vehicular air-conditioning system of the first embodiment;

FIG. 2 is a block diagram of an electric control unit of the vehicular air-conditioning system of the first embodiment;

FIG. 3 is a flowchart of control processing of the vehicular air-conditioning system of the first embodiment;

FIG. 4 is a flowchart of principal parts of control processing of the vehicular air-conditioning system of the first embodiment;

FIGS. 5 a to 5 d are explanatory views for judging the level of an air-conditioning heat load in a vehicular air-conditioning system of the first embodiment;

FIG. 6 is a time chart for explaining the operation of masking noise generating means in a vehicular air-conditioning system of the first embodiment;

FIG. 7 is a flowchart of principal parts of control processing of the vehicular air-conditioning system of the second embodiment; and

FIG. 8 is a view of the overall configuration of a vehicular air-conditioning system of the fourth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Using FIGS. 1 to 6, a first embodiment of the present invention will be explained. FIG. 1 is a view of the overall configuration of a vehicular air-conditioning system 1 using a vehicular refrigeration cycle apparatus 10 of the present embodiment. This vehicular air-conditioning system 1 is applied to a so-called hybrid car obtaining drive power for vehicle operation from an internal combustion engine (engine) EG and a drive-use electric motor DM. Note that, the arrows in the top, bottom, front, and back directions in FIG. 1 show the top, bottom, front, and back directions in the state mounting the vehicular air-conditioning system 1 in a vehicle.

The hybrid car of the present embodiment can operate or start the engine EG in accordance with the drive load etc. of the vehicle and switch between a driving state where it operates by obtaining drive power from both the engine EG and drive-use electric motor DM and a driving state where it operates by making the engine EG stop and obtains drive power from only the drive-use electric motor DM. Due to this, it is possible to improve the vehicle fuel efficiency compared with ordinary vehicles which obtain drive power for operating the vehicle from only an engine EG.

Next, the detailed configuration of the vehicular air-conditioning system 1 of the present embodiment will be explained. The vehicular air-conditioning system 1 of the present embodiment is provided with a vehicular refrigeration cycle apparatus 10, a cooling unit 20, an air-conditioning control unit 30 which is shown in FIG. 2, etc. Further, this vehicular air-conditioning system 1 enables pre air-conditioning which starts air-conditioning the inside of the cabin before the driver and passengers get in the vehicle.

First, the cooling unit 20 is arranged at the inside of an instrument panel at a front-most part of the cabin. The outer walls of the cooling unit 20 and the air passage for the air vented into the cabin are formed by a plastic casing. In the casing, an evaporator-use blower 21, evaporator 14, heater core, etc. are housed.

The evaporator-use blower 21 is a blowing means for taking in outside air (air from outside the cabin) or inside air (air from inside the cabin) which is introduced from an inside/outside air switching device, arranged at an upstream-most side of the air passage of the cabin venting air formed in the casing, and blowing it out toward the inside of the cabin. Specifically, the evaporator-use blower 21 is an electric blower which drives a sirocco fan by an electric motor and which is controlled in speed (blowing rate) by control voltage output from the air-conditioning control unit 30.

Inside the casing at the downstream side of the air flow from the evaporator-use blower 21, the evaporator 14 is arranged. The evaporator 14 is a cooling-use heat exchanger which exchanges heat between a refrigerant which is circulating through its inside and air which is blown from the evaporator-use blower 21. More specifically, the evaporator 14, together with a compressor 11, condenser 12, expansion valve 13, etc., forms the vapor compression type vehicular refrigeration cycle apparatus 10.

The compressor 11 is arranged inside the engine compartment (under the hood), takes in refrigerant, and compresses and discharges it at the vehicular refrigeration cycle apparatus 10. It is an electric compressor which drives a fixed capacity type compression mechanism with a fixed discharge capacity by an electric motor which operates by being supplied with electric power. This electric motor is a direct current (DC) motor which is controlled in operation (speed) by direct current voltage which is output from the air-conditioning control unit 30.

The condenser 12 is arranged in the engine compartment toward the front side of the vehicle and exchanges heat between the refrigerant which circulates inside it and the outside air which is blown in from the condenser-use blower 12 a so as to cause the refrigerant which is discharged from the compressor 11 to condense. This outside air is taken in from an air intake port provided at a front grille FG etc. which is arranged at the front side of the vehicle. Furthermore, liquid phase refrigerant which is condensed at the condenser 12 is stored in a not shown liquid receiver which is arranged at an outlet side of the condenser 12.

The condenser-use blower 12 a is an electric powered blower which is controlled in speed (blowing rate) by control voltage which is output from a later explained engine control unit 40. Furthermore, the condenser-use blower 12 a of the present embodiment blows outside air not only to the condenser 12, but also a radiator RD which is arranged in a cooling water circuit through which engine cooling water which cools the engine EG flows. Specifically, the outside air flows in the order of the condenser 12 to the radiator RD.

Further, as explained above, the condenser 12 and the radiator RD are blown with outside air which is taken in from an air intake port which is provided at the front grille FG etc., so the condenser-use blower 12 a, condenser 12, and radiator RD are arranged near the air intake port as shown in FIG. 1. For this reason, if the condenser-use blower 12 a operates, the operating noise of the condenser-use blower 12 a is easily heard by persons outside of the vehicle.

In other words, the operating noise of the condenser-use blower 12 a is noise which persons outside the vehicle are used to hearing. Therefore, in the present embodiment, as explained later, this blowing fan is made to operate also for generating masking noise helping to prevent noise which the driver or passengers or persons outside the vehicle are unfamiliar hearing, in the noise generated in the engine compartment, from ending up being heard. That is, the condenser-use blower 12 a of the present embodiment also functions as a masking noise generating means.

The expansion valve 13 is a pressure reducing means for reducing the pressure of and expanding the liquid phase refrigerant from the liquid receiver of the condenser 12. In the present embodiment, as this expansion valve 13, a temperature type expansion valve which has a sensing bulb which detects a degree of superheating of the evaporator 14 outlet side refrigerant based on the temperature and pressure of the evaporator 14 outlet side refrigerant and which uses a mechanical mechanism to adjust the cross-sectional area of the venturi passage so that the degree of superheating of the evaporator 14 outlet side refrigerant becomes within a predetermined range is employed.

The evaporator 14 makes the refrigerant which is reduced in pressure and expanded at the expansion valve 13 evaporate to cause an endothermic action on the refrigerant. Due to this, the evaporator 14 functions as a cooling-use heat exchanger which cools the air which is vented into the cabin at the cooling unit 20. Further, the refrigerant outlet side of the evaporator 14 is connected to the refrigerant intake port side of the compressor 11.

Further, in the casing at the downstream side in the air flow from the evaporator 14, a not shown heater core is arranged for reheating the cooling air which was cooled at the evaporator 14. The heater core is a heating-use heat exchanger which exchanges heat between the engine cooling water which cools the engine EG and the blown air after passing through the evaporator 14 so as to reheat the blown air after passing through the evaporator 14.

Further, in the vehicular air-conditioning system 1, the opening degree of an air mix door which adjusts the flow rate of cool air after passing through the evaporator 14 which uses the heater core for reheating is changed so as to adjust the temperature of the air-conditioning air blown into the cabin to the desired temperature of the driver and passengers. Further, the air-conditioning air which is adjusted in temperature is blown into the cabin from vents which are arranged in the casing at the downstream-most side in the air passage.

Note that, the opening degree of this air mix door is adjusted by an electric powered actuator which is controlled in operation by a control signal which is output from the air-conditioning control unit 30. Further, as the vents which are arranged in the casing at the downstream-most side in the air passage, specifically face vents which blow air-conditioning air toward the torsos of the driver and passengers in the cabin, foot vents which blow air-conditioning air toward the feet of the driver and passengers, and defroster vents which blow air-conditioning air toward the inside surface of the vehicle front window glass WG are provided.

Next, based on FIG. 2, an outline of the electrical control unit of the present embodiment will be explained. The air-conditioning control unit 30 and the engine control unit 40 use a known microprocessor including a CPU, ROM, RAM, etc. and peripheral circuits and perform various operations and processing to control the operations of the various devices connected to the output side based on a control program stored in the ROM.

At the output side of the engine control unit 40, various engine components forming the engine EG are connected. Specifically, a condenser-use blower 12 a, a not shown starter for starting the engine EG, a not shown drive circuit of fuel injectors which feed fuel to the engine EG, etc. are connected.

Further, at the input side of the engine control unit 40, a group of sensors 41 for engine control use which detect the operating states of the various engine components forming the engine EG are connected. As the group of sensors 41 for engine control use, there are not only an engine speed sensor which detects the engine speed Ne and other sensors which are arranged at the engine EG itself, but also an accelerator opening degree sensor which detects the accelerator opening degree, a vehicle speed sensor which detects the vehicle speed Vv, a water temperature sensor which detects the engine cooling water temperature Tw, and other sensors for engine control use.

At the output side of the air-conditioning control unit 30, an electric motor of the evaporator-use blower 21, an electric motor of the compressor 11, an electric powered actuator for the air mix door use, etc. are connected.

Further, at the input side of the air-conditioning control unit 30, an inside air sensor 31 which detects the cabin temperature Tr, an outside air sensor 32 which detects the ambient temperature Tam, a sunlight temperature sensor 33 which detects the sunlight temperature Ts in the cabin, a discharge pressure sensor 34 which detects a discharged refrigerant pressure Pd of the compressor 11, an evaporator temperature sensor 35 which detects the temperature Te of the air blown from the evaporator 14 (evaporator temperature), and various other sensors for air-conditioning control use are connected.

Furthermore, at the input side of the air-conditioning control unit 30, operating signals from various air-conditioning operating switches which are provided at a control panel 36 which is arranged near the instrument panel at the front of the inside of the cabin are input. As the various air-conditioning operating switches which are provided at the control panel 36, specifically, an on/off switch of the vehicular air-conditioning system 1, an auto switch which sets or releases automatic control of the vehicular air-conditioning system 1, a vent mode switch which changes the vent mode, a flow setting switch of the evaporator-use blower 21, a cabin temperature setting switch which sets the cabin temperature, etc. are provided.

Further, the air-conditioning control unit 30 has a remote control signal receiving unit 30 a which receives a signal from a wireless terminal (remote control) 50 carried by the driver or a passenger. The wireless terminal 50 is used by the driver or a passenger to output a request signal for the above-mentioned pre air-conditioning. Therefore, the driver or a passenger can start the vehicular air-conditioning system 1 for pre air-conditioning from a location away from the vehicle. Of course, at the time of pre air-conditioning, the engine EG is at a stop and the vehicle is also at a stop.

Furthermore, the air-conditioning control unit 30 and the engine control unit 40 are electrically connected with each other and can electrically communicate. Due to this, it is possible to use a detection signal or operating signal input to one control device as the basis for the other control device to control the operations of various devices connected to its output side. For example, the air-conditioning control unit 30 can use a vehicle speed detection signal which was input to the engine control unit 40 as the basis for control of the operation of the various devices which are connected to its output side.

Note that, the air-conditioning control unit 30 and the engine control unit 40 use a single control means for controlling the various air-conditioning control devices, but in the present embodiment, in the engine control unit 40, in particular the hardware and software for controlling the operation of the condenser-use blower 12 a which functions as the masking noise generating means are made the masking noise control means 40 a. Of course, the masking noise control means 40 a may also be configured as a separate control device for the engine control unit 40.

Next, the operation of the present embodiment with the above configuration will be explained. First, the basic operation of the engine control unit 40 will be explained. When the vehicle start switch is turned on and the vehicle is started up, the engine control unit 40 detects the driving load of the vehicle based on the detection signals of the above-mentioned engine control-use sensor group 41 and operates or stops the engine EG in accordance with the driving load.

Next, using FIGS. 3 and 4, the operation of the vehicular air-conditioning system 1 will be explained. FIG. 3 is a flowchart showing the control processing of a vehicular air-conditioning system 1 of the present embodiment. This control processing is started when the auto switch of the control panel 36 is turned on or when a remote control signal receiving unit 30 a receives a request signal for pre air-conditioning from the wireless terminal 50.

First, at step S1 of FIG. 3, processing is performed for initializing the flags, timer, etc. At the next step S2, the signals of the vehicle environment status used for the air-conditioning control, that is, the detection signals of the above sensor groups 31 to 35, 41, etc., the control signals output from the engine control device 40, and operating signals of the control panel 36 are read.

Next, at step S3, the control statuses of the electric motor of the evaporator-use blower 21, the electric motor of the compressor 11, the condenser-use blower 12 a, the electric powered actuator for the air mix door, etc. which are connected to the air-conditioning control unit 30 and the condenser-use blower 12 a which are connected to the engine control unit 40 and various other air-conditioning control devices are determined.

More specifically, at this step S3, first, the detection signals (specifically, cabin temperature Tr, ambient temperature Tam, and sunlight temperature Ts) and the operating signals (specifically, the cabin setting temperature Tset) which were read at step S2 are used as the basis to calculate the target blowing temperature TAO of the cabin venting air. Further, the control status is determined based on this target blowing temperature TAO and the detection signals read at step S3.

For example, the target blowing rate of the evaporator-use blower 21, that is, the control voltage BLW which is output to the electric motor of the evaporator-use blower 21, is determined based on the target blowing temperature TAO with reference to a control map stored in advance in the air-conditioning control unit 30 so that TAO becomes higher than the intermediate temperature at the time of a high temperature and at the time of a low temperature.

Further, regarding the refrigerant discharge capacity of the compressor 11, that is, the frequency of the AC voltage which is output to the electric motor of the compressor 11, the target evaporator blowing temperature TEO of the evaporator 14 is determined based on the target blowing temperature TAO with reference to a control map stored in advance in the air-conditioning control unit 30. Further, based on the difference between this target evaporator blowing temperature TEO and blowing air temperature Te, a feedback control means is used so that Te becomes close to TEO.

Further, the control signal which is output to the electric powered actuator for the air mix door use is determined using the target blowing temperature TAO, blowing air temperature Te, and engine cooling water temperature Tw so that the temperature of the air which is vented into the cabin becomes the desired temperature of the driver or a passenger.

Further, the control voltage which is output to the condenser-use blower 12 a is determined based on the engine cooling water temperature Tw with reference to the control map stored in advance in the air-conditioning control unit 30 so that it becomes higher along with the increase of the Tw.

At the next step S4, the control voltage which is to be output to the condenser-use blower 12 a used as the masking noise generating means is again determined. Therefore, the control step S4 of the present embodiment forms part of the software of the masking noise control means 40 a. The detailed content of this step S4 will be explained using the flowchart of FIG. 4.

First, at step S41, it is determined if the elapsed time Tm when the auto switch of the control panel 36 is turned on or when a signal requesting pre air-conditioning is received has become a predetermined reference time ΔTM or less. When it is determined at step S41 that the elapsed time Tm has become the predetermined reference time ΔTM or less, the routine proceeds to step S42, while when it is determined that the elapsed time Tm has not become the predetermined reference time ΔTM or less, the routine proceeds to step S47.

At step S42, it is determined if the engine EG has stopped. This determination is performed using the value of the engine speed Ne which is input through the engine control unit 40 and judging that the engine EG has stopped when the engine speed Ne is 0 rpm. When it is determined at step S42 that the engine EG has stopped, the routine proceeds to step S43, while when it is determined that the engine EG has not stopped, the routine proceeds to step S47.

At step S43, it is determined if the air-conditioning heat load of the vehicular refrigeration cycle apparatus 10 is high. This determination will be explained using the explanatory views of FIGS. 5 a to 5 d. The determination of whether the air-conditioning heat load of the vehicular refrigeration cycle apparatus 10 is high is performed by judging that the air-conditioning heat load is high when the value of the air-conditioning heat load flag Load which is found by the following formula F1 is “1” and judging that it is not high when the value of the air-conditioning heat load flag Load is 0″.

Load=f(TAM)×f(TR)×f(TE)×f(BLW)  (F1)

Here, f(TAM) is a flag for determining if the air-conditioning heat load is high based on the ambient temperature Tam. That is, when the ambient temperature Tam is high, to cool the cabin, the air-conditioning heat load becomes higher.

Therefore, in the present embodiment, specifically, as shown in FIG. 5 a, if the ambient temperature Tam is in the process of rising, when the predetermined reference temperature T1 or more, f(TAM) is made “1”, while if the ambient temperature Tam is in the process of descending, when the predetermined reference temperature T0 or less, f(TAM) is made “0”. The temperature difference between the reference temperature T1 and the reference temperature T0 is a value set as the hysteresis for preventing control hunting.

Further, f(TR) is a flag for determining if the air-conditioning heat load is high based on the inside air temperature Tr. That is, to cool the cabin when the inside air temperature Tr is high, the air-conditioning heat load becomes higher. Therefore, specifically, as shown in FIG. 5 b, in the same way as f(TAM), when the inside air temperature Tr becomes a predetermined reference temperature T3 or more, f(TR) is made “1”, while when it becomes a predetermined reference temperature T2 or less, f(TR) is made “0”.

Further, f(TE) is a flag for determining if the air-conditioning heat load is high based on the blowing air temperature Te. That is, when the blowing air temperature Te is low, it is necessary to lower the temperature of the air vented into the cabin and the air-conditioning heat load becomes higher. Therefore, specifically, as shown in FIG. 5 c, in the same way as f(TAM), when the blowing air temperature Te becomes a predetermined reference temperature T5 or more, f(TE) is made “0”, while when it becomes a predetermined reference temperature T4 or less, f(TE) is made “1”.

Further, f(BLW) is a flag for determining if the air-conditioning heat load is high based on the control voltage BLW which is output to the electric motor of the evaporator-use blower. 21 determined at step S3. That is, when the control voltage BLW is high, rapid heating or rapid cooling is being sought in the cabin, so the air-conditioning heat load becomes high.

Therefore, specifically, as shown in FIG. 5 d, in the same way as f(TAM), when the control voltage BLW becomes a predetermined reference voltage V1 or more, f(BLW) is made “1”, while when it becomes a predetermined reference voltage V0 or less, f(BLW) is made “0”.

Further, when it is determined at step S43 that the air-conditioning heat load is high, the routine proceeds to step S44 where the control voltage which is output from the condenser-use blower 12 a is made the highest value Hi, then the routine proceeds to step S46.

Further, when it is determined at step S43 that the air-conditioning heat load is not high, the routine proceeds to step S45 where the control voltage which is output to the condenser-use blower 12 a is made an intermediate voltage Lo of an extent where the condenser-use blower 12 a gives a sufficient level of noise for masking noise, then the routine proceeds to step S46. At step S46, the control voltage which is output to the electric motor of the compressor 11 is made “0”, that is, the operation of the compressor 11 is set to the stopped state, then the routine proceeds to step S5.

On the other hand, at step S47, it is determined if pre air-conditioning is underway. When it is determined at step S47 that pre air-conditioning is underway, the routine proceeds to step S43, while when it is determined that pre air-conditioning is not underway, the routine proceeds to step S5.

At step S5, as shown in FIG. 3, to obtain the control state determined at the above steps S3 and S4, control signals and control voltages are output from the air-conditioning control unit 30 and engine control unit 40 to the various devices 11, 12 a, 21, etc., then the routine proceeds to step S6.

At step S6, when an operation stopping signal is input by an operating switch on the control panel 36 to the air-conditioning control unit 30, the operations of the various air-conditioning devices are stopped and the system is made to stop. On the other hand, when an operation stopping signal is not input, the routine waits for predetermined control period τ, then returns to step S2.

Since the vehicular air-conditioning system 1 of the present embodiment operates as explained above, the air which is blown from the evaporator-use blower 21 is cooled by the evaporator 14. The cool air which was cooled by the evaporator 14 is adjusted in temperature to a desired temperature of the driver or passengers in accordance with the opening degree of the air mix door and is blown through the different vents to the inside of the cabin.

Further, when the inside air temperature Tr of the cabin air is made lower than the ambient temperature Tam by the air-conditioning air which is blown into the cabin, cooling of the cabin is realized, while when the inside air temperature Tr is higher than the ambient temperature Tam, heating of the cabin is realized.

Furthermore, according to the vehicular air-conditioning system 1 of the present embodiment, when it is determined at step S41 that the elapsed time Tm has become a predetermined reference time ΔTM or less and it is determined at step S42 that the engine EG is stopped, as shown in FIG. 6, at step S44 or S45, the condenser-use blower 12 a is made to generate masking noise and, at step S46, the compressor 11 is made to stop operating.

In other words, the masking noise control means 40 a makes the condenser-use blower 12 a configuring the masking noise generating means start to generate masking noise before the compressor 11 starts operating (specifically, exactly a reference time ΔTM before it). Due to this, it is possible to use the operating noise of the condenser-use blower 12 a which is familiar to persons outside the vehicle so as to mask the unfamiliar operating noise of the compressor 11 and to keep the unfamiliar operating noise of the compressor 11 from ending up being heard by persons outside the vehicle.

Furthermore, as explained at step S42, under conditions where no operating noise of the engine EG is generated and the operating noise of the compressor 11 is easily heard by the user, the masking noise is generated, so it is possible to effectively keep the unfamiliar operating noise of the compressor 11 from ending up being heard by persons outside of the vehicle and prevent the masking noise from being unnecessarily generated.

Note that, FIG. 6 is a time chart showing the changes along with time, in order from the top, of the operating state of the vehicular air-conditioning system 1, the speed of the electric motor of the compressor 11, the blowing rate of the condenser-use blower 12 a, and the air-conditioning heat load flag Load.

Furthermore, as explained at step S47, when, like at the time of pre air-conditioning, there is no operating noise of the engine EG, even if the elapsed time Tm exceeds a predetermined reference time A™, it is possible to make the condenser-use blower 12 a generate a masking noise. Therefore, it is possible to effectively prevent the operating noise of the compressor 11, which persons outside the vehicle are not used to hearing, from ending up being heard and the compressor 11 ending up being mistakenly considered to be malfunctioning.

Furthermore, as explained at step S43, along with an increase of the air-conditioning heat load of the vehicular refrigeration cycle apparatus 10, the blowing rate of the condenser-use blower 12 a is increased. Here, along with an increase of the air-conditioning heat load, the refrigerant discharge capacity (discharge flow) which is demanded from the compressor 11 is increased, so it is necessary to increase the speed of the compressor 11.

Therefore, as in the present embodiment, the blowing rate of the condenser-use blower 12 a is made to increase to make the volume of the masking noise increase along with an increase of the air-conditioning heat load so as to thereby avoid unnecessarily increasing the blowing rate of the condenser-use blower 12 a and wastefully consuming power.

Second Embodiment

In the above-mentioned first embodiment, the example of the engine EG being stopped at the control step S42 was explained, but in the present embodiment, as shown in the flowchart of FIG. 7, step S42 is changed to S42′. Specifically, at step S42′ of the present embodiment, it is determined if the vehicle speed Vv which is detected by the vehicle speed sensor has become a predetermined reference vehicle speed KVv or less.

That is, at step S42′, it is determined if the vehicle is at a stop or is being driven at a reference vehicle speed KVv or less. When it is determined at step S42′ that the vehicle speed Vv is the reference vehicle speed KVv or less, the routine proceeds to step S43, while when it is determined that the vehicle speed Vv is not the reference vehicle speed KVv or less, the routine proceeds to step S47. Note that, the reference vehicle speed KVv is determined as an extremely low speed such as parking where almost no road noise is generated.

The rest of the overall configuration and control modes are similar to the first embodiment. Therefore, in the vehicular air-conditioning system 1 of the present embodiment as well, in the same way as the first embodiment, it is possible to effectively keep the unfamiliar operating noise of the compressor 11 from ending up being heard by persons outside of the vehicle.

Furthermore, under vehicle operating conditions where no road noise is generated, it is possible to make the condenser-use blower 12 a generate masking noise. Therefore, it is possible to effectively prevent persons outside the vehicle from ending up hearing the unfamiliar operating noise of the compressor 11 and ending up mistakenly believing the compressor 11 is malfunctioning.

Third Embodiment

In the above-explained embodiments, the example where the masking noise generating means was configured by the condenser-use blower 12 a was explained, but in the present embodiment, the example where the masking noise generating means is configured by the evaporator-use blower 21 will be explained.

In this case, at step S44 shown in FIG. 4 of the first embodiment, it is sufficient to make the control voltage which is output to the evaporator-use blower 21 the highest value Hi and, at step S45, to make the control voltage which is output to the evaporator-use blower 21 an intermediate voltage Lo of an extent whereby the operating noise of the evaporator-use blower 21 becomes noise of a sufficient volume as the afore-mentioned masking noise. The rest of the overall configuration and control modes are the same as in the first embodiment.

Here, the operating noise of the evaporator-use blower 21 which blows air into the cabin is noise which persons inside the cabin are used to hearing. Therefore, by configuring the masking noise generating means by the evaporator-use blower 21, it is possible to effectively keep the unfamiliar operating noise of the electric compressor from ending up being heard by persons inside the cabin.

Fourth Embodiment

In the present embodiment, as shown in FIG. 8, the masking noise generating means is configured by an audio system 51 arranged in the engine compartment. Note that, FIG. 8 is a view of the overall configuration of a vehicular air-conditioning system 1 using the vehicular refrigeration cycle apparatus 10 of the present embodiment and is a view corresponding to FIG. 1 of the first embodiment.

This audio system 51 is arranged at an upper side of a tire house in the engine compartment and can generate noise close to the road noise, which persons outside the vehicle are used to hearing, as the masking noise by a control signal which is output from the air-conditioning control unit 30. Furthermore, it is possible to change the volume of the masking noise by the control signal which is output from the air-conditioning control unit 30.

Furthermore, in the present embodiment, at step S44 shown in FIG. 4 of the first embodiment, the volume of the audio system 51 is made the highest volume and, at step S45, the volume of the audio system 51 is made an intermediate volume of an extent giving a volume sufficient as masking noise. The rest of the overall configuration and control modes are the same as in the first embodiment.

Therefore, in the vehicular air-conditioning system 1 of the present embodiment as well, in the same way as the first embodiment, it is possible to keep the unfamiliar operating noise of the compressor 11 from ending up being heard by persons outside of the vehicle. Note that, in the present embodiment, as the audio system 51, an audio system 51 arranged in the engine compartment is employed, but the car stereo etc. may also be employed. Due to this, it is possible to keep the unfamiliar operating noise of the compressor 11 from ending up being heard by persons inside the cabin.

Other Embodiments

The present invention is not limited to the above embodiments and may be changed in various ways as explained below within the scope of the gist of the present invention:

(1) In the above-explained embodiments, the explanation of application of the vehicular refrigeration cycle apparatus of the present invention to an air-conditioning system for a hybrid car was explained, but the application of the present invention is not limited to this. For example, the apparatus may also be applied to a refrigerating apparatus, freezing apparatus, etc. for a hybrid car. Further, the application of the present invention is not limited to a hybrid car. For example, the invention is also effective when applied to a vehicle which does not generate the operating noise of an internal combustion engine such as an electric vehicle (including fuel cell vehicles).

(2) In the above-explained embodiments, the explanation of application of the vehicular refrigeration cycle apparatus of the present invention to a vehicular air-conditioning system configured to enable pre air-conditioning was explained, but the application of the present invention is not limited to this. Of course, the invention may also be applied to a vehicular air-conditioning system not configured to enable pre air-conditioning.

(3) The configurations explained in each of the above embodiments may be applied to the other embodiments as well. For example, it is possible to perform the determinations of both step S42 of the first embodiment and step S42′ of the second embodiment. Further, the masking noise generating means of the third and fourth embodiments can be applied to not only the first embodiment, but also the second embodiment.

(4) In the above-explained embodiments, the explanation of application of a vehicular air-conditioning system to which a vehicular refrigeration cycle apparatus of the present invention is applied to a so-called parallel type of hybrid car which can be driven by directly obtaining drive power from both an engine EG and drive-use electric motor DM of the hybrid car was explained, but the application of the vehicular air-conditioning system of the present invention is not limited to this.

For example, the invention may also be applied to a so-called serial type of hybrid car which uses the engine EG as a drive source of a generator, stores the generated electric power in a battery, and furthermore feeds the electric power which is stored in the battery to drive a drive-use electric motor DM and obtain drive power from the same.

While the invention has been described by reference to specific embodiments chosen for purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention. 

1. A vapor compression type vehicular refrigeration cycle apparatus adapted for use in a vehicle having a drive-use electric motor as a drive source for powering the vehicle and able to be driven by the drive power output from the drive-use electric motor, the vehicular refrigeration cycle apparatus comprising: an electric compressor which is driven by the supply of electric power and compresses and discharges a refrigerant; a masking noise generating means for generating masking noise helping to keep an operating noise of the electric compressor from being heard by a user; and a masking noise control means for controlling operation of the masking noise generating means, wherein the masking noise control means makes the masking noise generating means start to generate masking noise before the start of operation of the electric compressor.
 2. The vehicular refrigeration cycle apparatus as set forth in claim 1, wherein the masking noise control means makes said masking noise generating means generate masking noise when said vehicle is stopped or said vehicle is being driven at a predetermined reference vehicle speed or less.
 3. The vehicular refrigeration cycle apparatus as set forth in claim 1, wherein the masking noise generating means is configured by a condenser-use blower blowing air toward a condenser radiating heat from a refrigerant discharged from said electric compressor.
 4. The vehicular refrigeration cycle apparatus as set forth in claim 3, wherein said masking noise control means makes the blowing rate of the condenser-use blower increase along with an increase of a heat load of a refrigeration cycle.
 5. The vehicular refrigeration cycle apparatus as set forth in claim 1, wherein said masking noise generating means is configured by an evaporator-use blower which blows cabin venting air toward an evaporator which causes evaporation of a refrigerant taken into the electric compressor.
 6. The vehicular refrigeration cycle apparatus as set forth in claim 1, wherein said masking noise generating means is configured by an audio system which outputs predetermined noise. 